《增值税暂行条例实施细则》第二十三条规定“纳税人兼营免税项目或非应税项目(不包括固定资产在建工程)而无法准确划分进项税额的,按下列公式计算不得抵扣的进项税额: 不得抵扣的进项税额=当月全部进项税额×当月免税项目销售额、非应税 Article 23 of the Detailed Rules for the Implementation of the Provisional Regulations on Value Added Tax stipulates that "if the taxpayer can not accurately classify the input tax on duty-free items or non-taxable items (excluding construction in progress of fixed assets under construction), it shall be deducted according to the following formula Of the input tax: Input tax that can not be deducted = Total input tax of the current month × Sales of duty-free items in the current month, non-taxable